Protective cover



June 13, 1961 R, o. ROBINSON, JR, ETAL 2,987,999

. PROTECTIVE COVER Filed Feb. 12, 1959 2 Sheets-Sheet 1 FIG. 2.

FIG. I.

RALPH 0. ROBINSON, JR

THOMAS W. SHEPPARD 4 Y INVENTORY BY QBW ATTORNEYS June 13, 1961 R. o.ROBINSON, JR.. ETAL 2,987,999

PROTECTIVE COVER Filed Feb. 12, 1959 2 Sheets-Sheet 2 FIG. 3.

\ E u; gs u.

RALPH 0. ROBINSON, JR, THOMAS M. SHEPPARD INVENTORS BY Q '3 ATTOR/VEKS2,987,999 PROTECTIVE COVER Ralph G. Robinson, Jr., and Thomas W.Sheppard, Silver Spring, Md., assignors to the United States of Americaas represented by the Secretary of the Navy Filed Feb. 12, 1959, Ser.No. 792,936 3 Claims. (Cl. 102-925) The present invention relatesgenerally to protective devices for aerial vehicles; more particularlyit relates to improved displaceable seals for use with pressure probesor radomes of guided missiles.

Guided missiles require information regarding static pressures and/orram pressures in order to maneuver properly. Such missiles ordinarilyemploy pressure probes and/ or radomes having ports connected withappropriate equipment for measuring such static or ram pressures. It isimportant that these ports be kept free of foreign bodies if themeasuring equipment is to function properly. That is, during thehandling of guided missiles prior to launching thereof they may besubjected to a variety of environmental conditions which would bedeleterious to the proper functioning of pressure measuring equipment.Such conditions would include ocean waves, high winds, ice, shock, andvibration. Moreover, since the launching of a guided missile is acomplicated operation under optimum conditions, it is desirable thatseals be provided that will remain in place during handling andlaunching operations but which will be removed automatically andpositively after the missile has been launched.

One object of the present invention, therefore, is to provide adisplaceable seal which, in one embodiment, may be used to close theinlet port at the forward end of a guided missile radome prior tomissile launching for preventing the entry of foreign substances intothe interior of the missile, but which will be automatically andpositively displaced after missile launching for permitting operation ofapparatus within the missile.

The invention seeks, as another object, to provide a displaceable sealwhich, in another embodiment, maybe used for closing the port or portsof a missile nose probe until after missile launching.

A further object of the invention is to provide a displaceable sealwhich employs a low melting point alloy for securing said seal inposition on a missile nose or nose probe, which alloy may only be meltedby the coincident occurrence of a high velocity air flow and theresultant high stagnation temperature which occurs only during missileflight.

Still another object of the invention resides in the provision of adisplaceable seal which, in both embodiments, will be characterized byits extreme simplicity and ease of application.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings, wherein:

FIG. 1 is a front elevation showing one embodiment of the displaceableseal installed in operative position on the front end of a missileradome;

FIG. 2 is a sectional View on the line 2-2 of FIG. 1;

FIG. 3 is a side elevation, partly in section, showing a modifiedembodiment of the invention, the positions of the sections of the sealbeing shown in broken lines as they would appear immediately prior toseparation from a missile nose probe;

FIG. 4 is a front elevation of the embodiment shown in FIG. 3; and

FIG. 5 is a front elevation showing a modified slot arrangement for usewith the embodiment of FIGS. 3 and 4.

Patented June 13, 1961 Referring more particularly to the drawings, andfirst to FIGS. 1 and 2 therof, the numeral 10 indicates the forward endportion of a radome of an aerial missile. The nose of the portion 10 isformed with a port 11. A groove 12 is cut into the wall of the missileportion 10 near the nose thereof, and receives an annular deposit of lowmelting point alloy, as will be described in more detail hereinafter.

The seal of FIGS. 1 and 2 comprises a body 13 which is formed of fiatsheet metal and includes a hub 14 and preferably three radially directedequally spaced arms 15, 16 and 17, the arm 17 terminating in arelatively large circular tab 18. As shown in FIG. 2 the body 13 of theseal is mounted on the nose of the radome forward end portion 10 withthe hub 14 confronting the open end of the port 11. A sealing gasket 19is confined between the inner face of the hub 14 and the forward end ofthe nose of the portion 10, for effectively sealing'the port 11 andpreventing entry of foreign substances into the interior of the radome.The arms 15, 16 and 17 are bent rearwardly and have their free endportions anchored in a deposit 20 of low melting point alloy, such asCerrobend, produced by the Cerro de Pasco Corporation, New York, N.Y.The composition of Cerrobend is 50% bismuth, 26.7% lead, 13.3% tin and10% cadmium, and its melting temperature is 158 F. Other properties ofCerrobend are as follows:

In use, after installation of the seal on the radome portion 10, saidseal will effectively prevent entry of foreign substances into theinterior of the missile, with the overall result that delicate measuringequipment or other apparatus within the missile will not be adverselyaffected during missile handling prior to the launching thereof. Theproperties of the low melting point alloy Cerrobend are such that theseal will be firmly anchored in place and will withstand the roughhandling normally accorded missiles during transport thereof to thelaunching site.

'After the missile is launched, the high stagnation temperatureappearing at the nose thereof will quickly melt the Cerrobend deposit20, when air flow impinging on the tab 18 will displace the seal fromthe nose of the radome and thereby clear the port 11 for the entry ofair. Referring now to the embodiment of the invention shown in FIGS. 3,4 and 5, the numeral 21 indicates a pressure probe which is mounted onthe nose of a missile, a portion of which nose is shown at 22. The probe21 is formed in its side wall with an inlet port 23. The sealconstituting the embodiment shown in FIGS. 3, 4 and 5 includes a bodyhaving semi-cylindrical cooperating sections 24 and 25 which areconnected at their rear ends by curved tongue and groove hinge partsdefining displaceable hinges 27 and which are formed with flared forwardend portions 28 having concentric grooves 29 and 30 in their end faces.inwardly of the forward ends of the sections 24 and 25 are matingrecesses 31 which cooperate to define a chamber for receiving a normallycompressed helical spring 32. As best seen in FIG. 3,

the sections 24 and 25 snugly receive the forward end Normally retainingthe sections 24 and 25 in mating relation, for defining the seal, is adeposit of low melting point alloy 33, which may be of Cerrobend havingthe properties described in connection with the embodiment of theinvention as shown in FIGS. 1 and 2 of the drawings. The deposit 33completely fills the grooves 29 and 30 and covers the outer end faces ofthe sections 24 and 25 for retaining the sections in assembled relation,the hinge 27 securing the corresponding rear end portions of thesections 24 and 25 against displacement.

In use, when a missile utilizing the seal constructed as described aboveis fired, air flow at high temperature will impinge on the deposit 33for melting the same, when continuing air flow, accompanied by theexpanding effort of the spring 3 2, will urge the sections 24 and 25outwardly to the positions shown in dotted lines in FIG. 3. Furtheroutward movement, which will be brought about by the aforementioned airflow, will cause separation of the hinge 27, when the sections 24 and 25will be blown clear of the missile. Air flow may then enter the opening23 in the probe 21.

In lieu of the concentric grooves 29 and 30, parallel rectangulargrooves may be employed; such grooves are shown at 34 and 35 in FIG. 5.Also, if desired, supplemental sealing means may be placed over theopening 23 within the sections 24 and 25, as shown in dotted lines at 36in FIG. 3.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. In combination with an aerial missile having a nose portion formedwith a port, and a groove formed in the nose portion remote from theport, a displaceable seal having a body and a plurality of arms, saidbody confronting the port and said arms extending along the nose portionand terminating above said groove, a gasket between the body and theport for sealing said port, a deposit of low melting point alloy in thegroove and imbedding end portions of said arms for anchoring said sealon said nose portion, and means carried by one of said arms and actedupon by a high stagnation temperature high velocity air flow fordisplacing the seal from the nose portion upon melting of the alloydeposit during flight of the missile.

2. A displaceable seal as recited in claim 1, wherein said lastmentioned means consists of a flat sheet metal tab bent to extend intothe path of the air flow.

3. In combination with an aerial missile, a nose portion upon saidmissile, said nose portion terminating in a forward end having an airinlet port therein, said nose portion having a circumferential groove inthe exterior surface thereof, said groove being spaced from said inletport, a one piece displaceable seal for said opening, including a hubpositioned in confronting relationship to said forward end and overlyingsaid port, said hub having an area greater than the area of said port, aplurality of arms attached to said hub and arranged to extend backtherefrom along the exterior surface of said nose portion, said armsterminating above said groove, and a gasket positioned between said huband said forward end and completely closing said port, a deposit of alow melting point alloy in said groove, said deposit imbedding theterminal ends of said arms to thereby anchor said seal on said noseportion, said deposit being meltable by a high velocity, hightemperature air flow occurring subsequent to launching of the missile tothereby free said displaceable seal, and means upon one of said armsupon which said air flow impinges to thereby remove said seal from saidnose portion when said deposit has melted.

References Cited in the file of this patent UNITED STATES PATENTS 82,284Brown Sept. 22, 1868 651,969 Hartmann June 19, 1900 2,655,106 OBrienOct. 13, 1953 2,782,716 Johnston Feb. 26, 1957 2,782,717 Burri et a1Feb. 26, 1957 2,806,428 Weiss Sept. 17, 1957 FOREIGN PATENTS 12,401Great Britain 1905 267,920 Great Britain Nov. 24, 1927 OTHER REFERENCESAstronautics, vol. 2, No. 5, December 1957, pages 42 and 43, copy inDiv. 10 and Scientific Library.

